U.S. patent application number 13/881400 was filed with the patent office on 2013-09-26 for reinforced sulphur concrete.
The applicant listed for this patent is Juedu Austine, Yiu Chung Cheng, Michael David Lankshear, Cees Weijers. Invention is credited to Juedu Austine, Yiu Chung Cheng, Michael David Lankshear, Cees Weijers.
Application Number | 20130247795 13/881400 |
Document ID | / |
Family ID | 44227964 |
Filed Date | 2013-09-26 |
United States Patent
Application |
20130247795 |
Kind Code |
A1 |
Austine; Juedu ; et
al. |
September 26, 2013 |
REINFORCED SULPHUR CONCRETE
Abstract
Reinforced sulphur concrete wherein one or more metal
reinforcing members are in contact with sulphur concrete is
disclosed. The reinforced sulphur concrete comprises an adhesion
promoter that enhances the interaction between the sulphur and the
one or more metal reinforcing members.
Inventors: |
Austine; Juedu; (Bangalore,
IN) ; Cheng; Yiu Chung; (Amsterdam, NL) ;
Lankshear; Michael David; (Amsterdam, NL) ; Weijers;
Cees; (Eindhoven, NL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Austine; Juedu
Cheng; Yiu Chung
Lankshear; Michael David
Weijers; Cees |
Bangalore
Amsterdam
Amsterdam
Eindhoven |
|
IN
NL
NL
NL |
|
|
Family ID: |
44227964 |
Appl. No.: |
13/881400 |
Filed: |
October 26, 2011 |
PCT Filed: |
October 26, 2011 |
PCT NO: |
PCT/EP11/68711 |
371 Date: |
June 13, 2013 |
Current U.S.
Class: |
106/642 ;
106/640; 106/643; 264/128 |
Current CPC
Class: |
C04B 24/42 20130101;
C04B 28/36 20130101; C04B 32/02 20130101; E04C 5/01 20130101; E04C
5/015 20130101; C04B 24/42 20130101; C04B 14/00 20130101; C04B
28/36 20130101 |
Class at
Publication: |
106/642 ;
264/128; 106/640; 106/643 |
International
Class: |
C04B 24/42 20060101
C04B024/42 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 27, 2010 |
IN |
PCT/IN2010/000702 |
Claims
1. A reinforced sulphur concrete, comprising: one or more metal
reinforcing members are in contact with sulphur concrete, wherein
the sulphur concrete comprises sulphur, filler, and aggregate, and
wherein the reinforced sulphur concrete further comprises an
adhesion promoter that enhances the interaction between the sulphur
and the one or more metal reinforcing members.
2. A reinforced sulphur concrete according to claim 1, wherein the
adhesion promoter is an organosilane having one or more sulphide,
thiol, amine or alkenyl functional groups.
3. A reinforced sulphur concrete according to claim 2, wherein the
adhesion promoter is an organosilane of general molecular formula
(I): (R.sup.1O).sub.3Si--A--Si (OR.sup.2).sub.3 (I) wherein R.sup.1
and R.sup.2 are independently C.sub.1-6 alkyl and A is a divalent
functional group comprising one or more groups chosen from thiol,
sulphide, amine or alkenyl groups.
4. A reinforced sulphur concrete according to claim 3, wherein the
organosilane is bis(3-triethoxysilylpropyl)tetrasulphide.
5. A reinforced sulphur concrete according to claim 1, wherein the
one or more metal reinforcing members are steel reinforcing
members.
6. A reinforced sulphur concrete according to claim 1, wherein the
one or more metal reinforcing members have been treated with an
adhesion promoter prior to their incorporation into the sulphur
concrete.
7. A process for preparing reinforced sulphur concrete according to
claim 1, comprising steps of: (a) treating the one or more metal
reinforcing members with the adhesion promoter; (b) mixing sulphur,
aggregate, and filler at a temperature at which the sulphur is
molten; (c) pouring the molten sulphur admixture into a mould; (d)
before or after step (c), placing the metal reinforcing members in
the mould; and (e) cooling to a temperature at which the sulphur
solidifies.
8. A process for preparing sulphur concrete according to claim 1,
comprising steps of: (a) mixing sulphur, aggregate, filler, and
adhesion promoter at a temperature at which the sulphur is molten;
(b) pouring the molten sulphur admixture into a mould; (c) before
or after step (b), placing the metal reinforcing members in the
mould; and (d) cooling to a temperature at which the sulphur
solidifies.
9. A process for preparing reinforced sulphur concrete according to
claim 7, wherein, before step (a), there is a step of cleaning the
one or more metal reinforcing members.
Description
FIELD OF THE INVENTION
[0001] The present invention provides reinforced sulphur concrete
and a process for the preparation of reinforced sulphur
concrete.
BACKGROUND OF THE INVENTION
[0002] Elemental sulphur or modified sulphur can be used to bind
aggregate and filler, thereby providing sulphur concrete. Sulphur
concrete can be used in a variety of pre-cast concrete applications
such as marine defenses, paving slabs, road barriers and retaining
walls.
[0003] Concrete materials are typically strong under compression
yet demonstrate weakness under extension. Their strength may be
improved by incorporating metal reinforcement in the areas of the
concrete subject to extension. The inventors have found that, in
sulphur concrete, the metal reinforcing members may not adhere well
to the sulphur and this can cause problems. The metal may loosen
from the sulphur and the metal-sulphur interface may become
saturated due to capillary uptake of water, leading to corrosion of
the metal and failure of the concrete.
[0004] JP 2007 270553 discloses a construction method for preparing
metal-reinforced sulphur concrete, but does not address the problem
of improving the metal-sulphur interface.
[0005] The present inventors have sought to provide improved
reinforced sulphur concrete, wherein there is effective adhesion
between the sulphur and the metal reinforcing members.
SUMMARY OF THE INVENTION
[0006] The inventors have found that adhesion promoters may be
incorporated into sulphur concrete, improving the adhesion between
the sulphur and the metal reinforcing members. Accordingly, the
present invention provides reinforced sulphur concrete wherein one
or more metal reinforcing members are in contact with sulphur
concrete, wherein the sulphur concrete comprises sulphur, filler,
aggregate and, optionally, modifier, and wherein the reinforced
sulphur concrete comprises an adhesion promoter that enhances the
interaction between the sulphur and the one or more metal
reinforcing members.
DETAILED DESCRIPTION OF THE INVENTION
[0007] In the reinforced sulphur concrete of the invention, one or
more metal reinforcing members are in contact with sulphur
concrete. Preferably the one or more metal reinforcing members are
encased in sulphur concrete. The metal reinforcing members may be
any conventional reinforcements such as bars, grids, plates,
fibres, flakes, beams or boxes. The metal reinforcing members are
preferably bars, grids or plates; most preferably bars. The metal
reinforcing members are preferably steel reinforcing members, but
may also be made of aluminium or an alloy such as brass.
[0008] The sulphur concrete comprises sulphur, filler, aggregate
and, optionally, modifier. Preferably the sulphur concrete
comprises from 5 to 40wt % sulphur, from 25 to 50wt % coarse
aggregate, from 20 to 40wt % fine aggregate and from 1 to 10wt %
filler. The weight percentages are based upon the weight of the
sulphur concrete. Coarse aggregate is particulate inorganic
material having average diameter from 5 to 40 mm. Fine aggregate is
particulate inorganic material having average diameter from 0.1 to
5 mm. Filler is particulate inorganic material having average
diameter from 0.1 .mu.m to 0.1 mm. The preferred amounts of
sulphur, aggregate and filler are a balance between incorporating
sufficient sulphur to bind the aggregate and filler and
incorporating sufficient aggregate and filler to provide mechanical
strength, whilst ensuring that the mixture has a suitable working
viscosity during sulphur concrete manufacture.
[0009] The sulphur concrete optionally comprises modifier.
[0010] Sulphur modifiers are known to the skilled person and are
compounds that improve the durability of sulphur concrete. The
amount of modifier is preferably from 0.001 to 1 wt %, more
preferably from 0.01 to 0.6 wt % and most preferably from 0.01 to
0.4 wt %. The modifier is typically one of the most expensive
components in the concrete, so it is desirable to limit the amount
of modifier. Suitable modifiers include olefinic modifiers such as
5 ethylidene-2-norbornene (ENB), 5 vinyl-2-norbornene (VNB),
dicyclopentadiene, limonene or styrene. Alternatively, the modifier
may be an organosilane or an organotitanate.
[0011] The reinforced sulphur concrete comprises an adhesion
promoter that enhances the interaction between the sulphur and the
one or more metal reinforcing members. The adhesion promoter is
preferably an organosilane, more preferably an organosilane having
one or more sulphide, thiol, amine or alkenyl functional groups.
The amount of adhesion promoter is preferably less than 1 wt %,
more preferably less than 0.1 wt %, based upon the weight of the
reinforced sulphur concrete. It is desirable to incorporate the
smallest possible amount of adhesion promoter that achieves the
required improvement in properties because the adhesion promoter is
typically a costly component of the reinforced sulphur
concrete.
[0012] Organosilanes are compounds having at least one
carbon-silicon bond or at least one carbon-oxygen-silicon group.
The organosilanes that are suitably used as adhesion promoters are
also suitably used as modifiers in the sulphur concrete.
[0013] Preferred organosilanes are organosilanes of the general
molecular formula (I):
(R.sup.1O).sub.3Si--A--Si (OR.sup.2).sub.3 (I)
wherein R.sup.1 and R.sup.2 are independently C.sub.1-6 alkyl or
hydrogen, and A is a divalent functional group comprising one or
more groups chosen from thiol, sulphide, amine or alkenyl groups.
Preferably R.sup.1 and R.sup.2 are ethyl or methyl groups, or
hydrogen. Preferably A is a polysulphide group of formula
--(CH.sub.2).sub.x--S.sub.y--(CH.sub.2).sub.z-- wherein x is an
integer from 1 to 4, y is an integer from 2 to 8, and z is an
integer from 1 to 4. Most preferably x and z are the same and y is
from 2 to 6. Particularly preferred organosilanes are
bis(3-triethoxysilylpropyl)tetrasulphide and
bis(3-triethoxysilylpropyl)disulphide.
[0014] The organosilane is alternatively of general formula
(II):
(R.sup.3O).sub.3Si--A' (II)
wherein R.sup.3 is C.sub.1-6 alkyl or hydrogen, and A' is a
univalent functional group comprising one or more groups chosen
from thiol, sulphide, amine or alkenyl groups. Preferably R.sup.3
is an ethyl or methyl group or hydrogen. Preferably, A' is a thiol
group or sulphide group, having the formula
--(CH.sub.2).sub.p--S.sub.q--(CH.sub.2).sub.r--H, wherein p is an
integer from 1 to 4, q is an integer from 1 to 8 and r is 0 or an
integer from 1 to 4. In one embodiment, q is 1 and r is 0, such
that A' is a thiol group. In another embodiment, q is from 2 to 8
and r is from 1 to 4, such that A' is a polysulphide group. In
another preferred embodiment, A' is a primary amine group of
formula --(CH.sub.2).sub.n--NH.sub.2, wherein n is an integer from
1 to 4. In yet another preferred embodiment, A' is an alkenyl group
of formula --(CH.sub.2).sub.m--X, wherein m is an integer from 0 to
4 and X is an alkenyl group. Possible X groups are shown below:
##STR00001##
[0015] The adhesion promoter may be incorporated into the
reinforced sulphur concrete simply by adding the adhesion promoter
to the sulphur concrete mix such that the adhesion promoter is
dispersed throughout the sulphur concrete. In one embodiment of the
invention, the adhesion promoter is concentrated at the interface
of the reinforcing members and the sulphur concrete. This can be
achieved by treating the one or more metal reinforcing members with
the adhesion promoter prior to their incorporation into the sulphur
concrete. The one or more metal reinforcing members may be treated
with an adhesion promoter which is in the form of a solution or
which may undiluted. If a solution is used, the solvent is
preferably isopropyl alcohol and/or water. The adhesion promoter
(in solution or undiluted) may be applied by any suitable means
such as dipping, spraying or painting.
[0016] Preferably any excess adhesion promoter is removed by
rinsing and the metal reinforcing members are suitably dried.
[0017] The sulphur concrete according to the invention is
preferably prepared by a process comprising steps of: [0018] (a)
treating the one or more metal reinforcing members with an adhesion
promoter; [0019] (b) mixing sulphur, aggregate, filler and,
optionally, modifier at a temperature at which the sulphur is
molten; [0020] (c) pouring the molten sulphur admixture into a
mould; [0021] (d) before or after step (c), placing the metal
reinforcing members in the mould; and [0022] (e) cooling to a
temperature at which the sulphur solidifies.
[0023] Alternatively, the sulphur concrete according to the
invention may be prepared by a process comprising steps of: [0024]
(a) mixing sulphur, aggregate, filler, adhesion promoter and,
optionally, modifier at a temperature at which the sulphur is
molten; [0025] (b) pouring the molten sulphur admixture into a
mould; [0026] (c) before or after step (b), placing the metal
reinforcing members in the mould; and [0027] (d) cooling to a
temperature at which the sulphur solidifies.
[0028] In both processes of the invention, the sulphur and other
components are mixed at a temperature at which the sulphur is
molten, i.e. typically above 120.degree. C., preferably in the
range of from 120 to 150.degree. C., more preferably in the range
of from 125 to 140.degree. C. The metal reinforcing members are
preferably placed into the mould before the molten sulphur
admixture is poured into the mould, but may alternatively be placed
into the molten sulphur admixture whilst it is in the mould. On
cooling, the sulphur solidifies and the sulphur concrete article
may be demoulded.
[0029] Preferably the one or more metal reinforcing members are
cleaned prior to their exposure to the adhesion promoter. Such a
pre-cleaning step can remove contaminants from the surfaces of the
one or more metal reinforcing members, and this can lead to further
improved adhesion between the metal reinforcing members and the
sulphur. The cleaning step is suitably any conventional cleaning
method such as washing with water, ultra-sonic cleaning in acetone,
polishing with grit paper or treatment with Piranha solution
(mixture of sulphuric acid and hydrogen peroxide).
[0030] Sulphur concrete articles produced according to the
invention can be used in a variety of pre-cast concrete
applications such as marine defenses, paving slabs, road barriers
and retaining walls.
EXAMPLES
[0031] The invention is further illustrated by means of the
following non-limiting examples.
Adhesion Tests
[0032] Adhesion tests were carried out to assess whether
organosilanes improve the adhesion between sulphur and metal
surfaces. Two organosilanes were used:
bis[3-(tri-ethoxysilyl)propyl]tetrasulfide (TESPT) and
n-propyltriethoxysilane (PTES). Three metals were used: stainless
steel, brass and aluminium.
[0033] The organosilanes were hydrolysed before they were used to
treat the metals. A mixture of 2-propanol (IPA), organosilane and
water were loaded in a round bottom flask, (ratio was 90% IPA: 5%
organosilane: 5% water (weight %)). The mixture was stirred at
ambient temperature for at least two days before use.
[0034] The metal plates were treated by dipping into a solution of
hydrolysed coupling agent for one minute. The metal was placed into
a silicon mould and placed in a oven at 115.degree. C. for 30
minutes. For comparative examples without organosilane treatment,
the metal was firstly wiped with a tissue and was placed in the
silicon mould before putting into the oven for the same time and
temperature.
[0035] Sulphur was melted and then poured over the preheated metal
plate, so that the silicon mould was at least half filled. Then the
liquid was left to solidify and was demoulded afterwards. The cup
was turned upside down so that the metal surface was on top and
could be used for strength measurement.
[0036] The equipment used for the measurement of adhesion strength
was a Pull-Off adhesion tester. This piece of equipment is used to
test adhesion, mainly in coating industries. A dolly was glued to
the metal plate and, after drying of the glue, force was applied to
pull the metal plate off the sulphur, thereby measuring the
adhesion strength between sulphur and metal.
[0037] Table 1 shows the adhesion measurement results for
comparative examples with no organosilane treatment (comparative
examples 1, 3 and 5), examples of the invention having been treated
with TESPT (examples 1, 2 and 3) and comparative examples having
been treated with PTES (comparative examples 2, 4, and 6).
TABLE-US-00001 TABLE 1 Force required Metal Organosilane (MPa)
Comparative Stainless Steel None 0.47 Example 1 Example 1 Stainless
Steel TESPT 0.90 Comparative Stainless Steel PTES 0.15 Example 2
Comparative Brass None 0.70 Example 3 Example 2 Brass TESPT 0.75
Comparative Brass PTES 0.15 Example 4 Comparative Aluminium None
0.22 Example 5 Example 3 Aluminium TESPT 0.55 Comparative Aluminium
PTES 0.15 Example 6
[0038] The results show that treatment with TESPT considerably
improved the adhesion between the sulphur and the metal (steel,
brass and aluminium); more force was required to remove the metal
plate from the sulphur when the metal plate had been treated with
TESPT. By contrast, treatment with PTES (an organosilane that does
not have a sulphide, thiol, amine or alkenyl functional group) led
to decreased adhesion between the sulphur and the metal.
* * * * *